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Memory settings for Abaqus/Explicit in a HPC cluster

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Konsti

Structural
May 11, 2021
23
Hello,

Anyone with high performance computing experience here? I am executing a large Abaqus/Explicit model in a cluster using the following command:

bsub -J Abaqus_solve -W 4:00 -n 5 -R "rusage[mem=4096]" abaqus job=3Dframe input=3Dframe.inp cpus=5

The memory setting is 80% by default so I'm not explicitly defining it. Note that due to the LSF queue system I have to request cpus and memory from the HPC first (-n, -R), and then from abaqus after (cpus). Also note that the LSF memory request is per core.

When I use one core (n=1 and cpus=1) the analysis runs without issues. However, when I use parallel processing I sometimes (one in ten) get a memory error: apparently Abaqus is asking for 25% more memory than what I have allocated in the bsub option (-R). This is very bizzare and I cannot reproduce it at will; it seems random. I have tried setting memory="90%" in the abaqus command line, but still no change to this issue. I will now try using the following options:

bsub -J Abaqus_solve -W 4:00 -n 5 -R "rusage[mem=4096]" abaqus job=3Dframe cpus=5 parallel=domain domains=5 dynamic_load_balancing=off mp_mode=threads memory="20480"

Changes from last attempt: not specifying input file (done automatically), setting domain parallelisation with mp_mode=threads and number of domains=number of cores, turning off dynamic load balancing (since I have predefined fields in my analysis, which are not supported by DLB), and setting memory explicitly to 20GB (5 cores*4GB each).

Is there something awfully wrong that I am doing here?

Thank you in advance for your help,

Konstantinos
 
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Which version of Abaqus do you use ? This software's HPC capabilities (especially for explicit solver) are constantly upgraded and it's best to use the newest release (including hot fixes).
 
Hi Mr/Ms heroic FEA way,

I use Abaqus/2021 and I have had the same issue also with the 2020 and 2019 versions.
 
Issues like that happen from time to time and they should be reported to Dassault Systemes Simulia support office. There's a chance that Abaqus developers will fix this problem in near future after such report if they manage to recreate the error.
 
It would be best to report this to your local Simulia support office (the DS partner that provided you with the software itself). They will try to recreate this issue first and then they can submit a Service Request directly to Dassault Systemes. There are some dedicated apps for request submissions for clients (3DSupport App and DSx.Client Care).
 
I have had no luck trying to contact 3DS before. Also, our cluster support receive no support for Abaqus, apparently. I will try contacting another IT department.
Thank you for the tips. If you have any other ideas please let me know..
Konsti
 
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